DESCRIPTION (Unedited Applicant's Abstract): The goal of this project is to develop an advanced, miniaturized, all solid hybrid capacitor type (Electrochemical-Electrolytic) for the next generation of implantable defibrillators. The capacitor consists of a modified porous tantalum oxide structure of a high-voltage electrolytic type anode, solid ionomer electrolyte and electrochemical redox pseudocapacitance Ruthenium oxide type cathode. By combining the advantages of the electrochemical capacitor and the electrolytic capacitor, the proposed design will yield a high voltage, small volume and low Equivalent Series Resistance (ESR) device with simplified packaging process. Besides the potential for volume and/or mass reductions, which will significantly contribute to the clinically important efforts of reducing the Size of the present implantable defibrillator, other inherent characteristics of hybrid capacitor could be critical drivers for selection of this technology for implantable defibrillators. High reliability and safety have also significant impact on this technology. Phase I will identify methods of improving tantalum anode structure, solid ionomer electrolyte, and catalyst particulate of the cathode to increase the energy density and reduce the size the capacitor resulting in more efficient charge extraction and a more rapid rate of capacitor discharge. Packaging strategies will be developed and identified. A unit capacitor will be fabricated and operated to demonstrate concept feasibility. PROPOSED COMMERCIAL APPLICATION: The commercial potential of this application is significant, there are critical need for reduced size, high energy density capacitor for the implantable defibrillators, in addition this technologies are needed to open up a wide range for making other implantable support devices. i.e., for nerve and muscle stimulation, possible, thus helping to increase worldwide the market share of the US companies in these device segment.